Structures and functions in living organisms Flashcards
1
Q
What is the order of level of organisation
A
Organelles
Cells
Tissues
Organs
Organ systems
2
Q
Describe each level of organisation
A
Organelles: specialized subcellular structures found within living cells
Cells : basic structural unit of living organisms
Tissue : groups of cells, either similar structures working together to perform the same function
Organs : groups of tissues, working together to perform specific functions
Organ systems : groups of organs with similar functions, working together to perform body functions
3
Q
Function of nucleus
A
• contains genetic material
• controls cell activity
4
Q
Function of cytoplasm
A
• liquid substance where chemical reactions occur
• contains enzymes
5
Q
Function of cell membrane
A
• controls what enters and leaves the cell
6
Q
Function of mitochondria
A
• where aerobic respiration reactions occur
• provides energy for the cell
7
Q
Function of ribosomes
A
• where protein synthesis occurs
8
Q
Function of chloroplast
A
• where photosynthesis takes place
• contains chlorophyll pigment, which harvests light needed for photosynthesis
9
Q
Function of permanent vacuole
A
• contains cell sap
• found within cytoplasm
• improves cells rigidity
10
Q
Function of cell wall
A
• provides strength to cell
• made from cellulose (in plants)
• made from chitin (in fungi)
11
Q
Biological molecules:
A
Carbohydrates
Proteins
Lipids
12
Q
What are carbohydrates
A
• made of carbon, oxygen, and hydrogen
• are polymers that break down into simple sugars
13
Q
What are proteins
A
• made of carbon, oxygen, hydrogen, sulfur, nitrogen and phosphorus
• are polymers that break down into its monomer : amino acids
14
Q
What are lipids
A
• made of carbon, oxygen, and hydrogen
• large polymers that break down into 3 fatty acid molecules and a glycerol molecule
15
Q
Test for glucose
A
- Add sample solution into test tube
- Add drops of Benedicts solution into test tube
- heat in water bath at 60-70°C for 5 mins
- take test tube out and record colour
POSITIVE = Brick red
NEGATIVE = remains blue
16
Q
Test for starch
A
- Use pipette and add sample solution onto tile
- Add drops of iodine solution and
- Leave for 1 minute and record colour change
POSITIVE = Blue-black
NEGATIVE = remains brown
17
Q
Test for protein
A
- Add sample solution into test tube
- Add drops of Buirets solution into test tube 3. Leave for 1 minute and record colour change
POSITIVE = purple
NEGATIVE = remains blue
18
Q
Test for fats
A
- Add 2cm³ of ethanol to test solution
- Add 2cm³ of distilled water
- Leave for 3 minutes and record colour change
POSITIVE = milky white emulsion formed
NGATIVE = remains colourless
18
Q
Role of enzymes
A
Biological catalysts
Enzymes are proteins that help speed up chemical reactions in our bodies.
18
Q
Effect of temperature on enzymes activity
A
•optimum is 37°C
•rate of reaction increases with increase in temperature until optimum
•above optimum, rate of reaction rapidly decreases and eventually reaction stops
• when temperature becomes too hot the bonds break
• This changes shape of active site, so substrate can’t fit
• enzymes is denatured and can’t work anymore
19
Q
Practical : investigate how enzyme activity can be affected by changes in temperature
A
- Starch solution is heated to set temperature
- Amylase is added
- Iodine is added to each tile after a minute
- measure time taken until iodine stops going blue-black
- repeat with different temperatures
20
Q
Effect of pH on enzymes activity
A
• optimum pH is 7 (most of the time)
• if pH is too high or low, forces that hold amino acid chains will be affected
• This changes the shape of the active site, so substrate doesn’t fit
• enzyme is denatured
21
Q
Describe diffusion
A
• The net movement of particles from high to low concentration
• Passive process (no energy required)
22
Q
Describe osmosis
A
• The movement of water from a less to higher concentration through partially permeable membrane
• high water potential to low water potential = down concentration gradient
• Passive process
23
Describe active transport
• The movement of particles from low to high concentration against the concentration gradient
• requires energy
24
Factors that affect the rate of movement
•Concentration gradient
• temperature
• surface area:volume ratio
• distance
25
Practical : investigating osmosis in potatoes
1. place different sucrose solutions (including 0% for a control) in different boiling tube's
2. Dry potato strip on a paper towel and measure masses
3. Place each strip into each sucrose solution for 20 mins
4. record how each mass has changed
4. repeat tests at each solution several times w same potato strip mass
26
The process of photosynthesis
• The process of making glucose from sunlight in the leaves of plants
• Endothermic reaction
• light converted to chemical energy within chloroplasts
27
equation for photosynthesis
. light
carbon dioxide + ---> glucose + water oxygen
CO² + H2O ---> C⁶H¹²O⁶ + O²
28
Factors affecting photosynthesis
• Temperature
• Light intensity
• Carbon dioxide concentration
29
Structure of a leaf
waxy cuticle
upper epidermis
palisade mesophyll
spongy mesophyll
lower epidermis
guard cell
stomata
30
Describe waxy cuticle
•helps reduce water loss by evaporation
•protective layer found at top of leaf
31
Describe upper epidermis
very thin and transparent to let light in to the palisade mesophyll
32
Describe palisade mesophyll
•contains lots of chloroplast so that photosynthesis can happen rapidly
33
Describe spongy mesophyll
• has lots of air spaces to allow gases to diffuse in and our of cell faster
• as it increases the surface area to volume ratio
34
Describe Lower epidermis
• contains guard cells and stomata
35
Describe guard cell
• kidney shaped cells
• open and close the stomata by absorbing or losing water
• when lots of water is available, the cell fills and open stomata
36
Describe stomata
• where gas exchange and loss of water by evapotion takes place
• opens during day, closes at night
37
What are the mineral ions and what are they needed for
Magnesium :
• required for chlorophyll production
• deficiency --> leaves to turn yellow
Nitrate :
• required to produce amino acids
• deficiency --> stunted growth and yellow leaves
38
What should a balanced diet include
carbohydrates
proteins
lipids
Fibre
vitamins
minerals
water
39
Source and function of carbohydrates
Source : bread, cereal, potatoes, rice
Function : high energy source
40
Source and function of proteins
Source : meat, fish, eggs
Function : for growth and repair
41
Source and function of lipids
Source: butter, oil, nutes
Function : high energy source and for insulation
42
Source and function of fibre
Source : vegetables, bran
Function : to provide roughage to keep food moving through gut. defiency --> constipation
43
Source and function of vitamin A
Source : carrots, green vegetables
Function : needed for vision ( especially in dark), and growth
44
Source and function of vitamin C
Source:citrus fruits, broccoli, peppers
Function : helps to absorb iron
45
Source and function of vitamin D
Source : margarine, oily fish
Function : helps to absorb calcium
46
Source and function of Calcium
Source : milk
Function: for bone and teeth strength, deficiency --> rickets
47
Source and function of iron
Source : red meat
Function : needed for hemoglobin, deficiency --> anaemia
48
Source and function of water
Source : water, juice, milk
Function : needed for cell reactions to take place
49
Factors affecting energy requirements
age
activity levels
pregnancy
50
Human alimentary canal
the passage food moves through once it has been eaten
51
function of mouth
• mechanical digestion
• chemical digestion
• Salivary glands produce saliva to lubricate food do it can be swallowed easily
52
function of oesophagus
• tube from mouth to stomach
• food moves down due to peristalsis (undirectional wave like contractions) created by muscles that create a sweeping like action
53
function of pancreas
• produces carbohydrase, protease, and lipase enzymes
• secrets enzymes unto stomachache and small intestine
54
function of stomach
• gastric juice released from stomach lining when it detects food in stomach
• peristalsis also occurs here
55
function of small intestine
Duodenum:
• first part
• carbohyrases, proteases, and lipases digest food here
•bile is released
• peristalsis aldo occurs here
Ileum :
• lined with vili to maximize absorption of digested soluble molecules into blood
56
Bile
• produced by liver
• stored in gallbladder
• it is alkaline, neutralizes hydrochloric acid from stomach
• breaks down large drops of fat into smaller ones ( emulsifies it)
57
function of large intestine
• water is absorbed here to produce faeces
• faeces stored in rectum and removed through anus
58
function of rectum
stores faeces before egestion
59
how does peristalsis work to push food though the gut
muscles contract in a wave like fashion which pushes food along
60
what enzymes break starch down to glucose
maltose and amylase
61
what group of enzymes break proteins down into amino acids
proteases
62
what group of enzymes break lipids down into glycerin and fatty acids
lipases
63
what does bile do
•bile neutralizes the stomach acid, provides alkaline conditions for digestive enzymes in small intestine
• bile emulsifies fat
64
where is bile produced
in the liver
65
where is bile stored
in the gallbladder
66
How is the small intestine adapted for absorption
• large surface area
• thin walls - easy transfer of nutrients
• rich blood supply - capillaries carry away absorbed nutrients
67
purpose of respiration
to produce energy in the form of ATP from larger molecules (like sugars)
68
What type of reaction is respiration
exothermic reaction
69
When does aerobic respiration take place
when there is plenty of oxygen available
70
what is symbol equation for aerobic respiration
C⁶H¹²O⁶ + 6O² ---> 6CO² + 6H²O + energy
71
word equation for aerobic respiration
glucose + oxygen ---> carbon dioxide + water
72
When does anaerobic respiration take place
when there's no oxygen available
73
equation for anaerobic respiration in animals
Glucose ---> lactic acid + energy
74
which type of respiration produces more ATP
aerobic respiration produces more ATP
75
word equation for anaerobic respiration in plants
glucose ---> ethanol + carbon dioxide
76
describe general structure of lungs
• trachea branches into two bronchi
• bronchi branch into bronchioles
• bronchioles terminate in alveoli
77
describe structure of ribs
• bone 'cage' surrounding the lungs
• provides protection of internal organs
78
describe intercostal muscle
• muscles found between ribs
• controls inhalation and exhalation
79
describe diaphragm
• muscular dome at bottom of thorax
• changes the pressure to control inhalation and exhalation
80
describe trachea
• the windpipe
• where air enters thorax and flows to lungs
81
describe bronchi
• trachea divides into 2 bronchi, one to each lunch
82
describe bronchioles
the bronchi further divide into smaller tube's that connect to alveoli
83
describe alveoli
tiny air sacs where gas exchange occurs
84
describe pleural membranes
• found on outside of lungs and inside of chest cavity
• lubricates the lungs
• reduces friction when breathing
85
What happens to intercostal muscles and diaphragm in inhalation and exhalation
INHALATION
intercostal muscles : contract
diaphragm : contracts downwards
EXHALATION
intercostal muscles : relax
diaphragm : relaxes upwards
86
alveoli adaptations
thin cell walls - one cell thick so shorter distance of diffusion
folded - to increase surface area for diffusion
large network of tiny capillaries - increases concentration gradient, oxygen can diffuse into blood and CO² can be breathed out
87
3 health issues caused by smoking
• cancer
• bronchitis
• coronary heart disease
88
how does smokers cough begin
• cilia on cells lining trachea waft mucus containing dirt out of lungs
• smoking can kill cells lining trachea
• Build-up of mucus in lungs can cause people to develop smokers cough
89
2 reasons why unicellular organisms can rely on diffusion only
• have large surface area to volume ratio due to their size
• have low metabolic demands
90
What does the phloem transport
sugars like sucrose
91
what direction does the phloem transport sugars
• transports sugars up and down plant
• from source to sink
92
what does xylem transport
water and minerals
93
what direction does the xylem transport water and minerals
• up the plants
• from the roots to the leaves
94
How is the xylem adapted to transport water
• waterproofed by using a substance called lignin
• xylem cells are dead and have no organelles so more space for water
95
Describe translocation
• the movement of sugars up or down the phloem from source to sink
• using energy
96
4 components of blood
• red blood cells
• white blood cells
• platelets
• plasma
97
describe platelets
• small fragments of cells
• involved in blood clotting
98
how are red blood cells adapted yo their function
• contains haemoglobin to carry oxygen
• bioncaoe shape to maximize surface area and allow them to squeeze through capillaries
• no nucleus to maximize space for haemoglobin
99
describe and purpose of plasma
• liquid part of blood
• acts as transport medium foe CO², hormones, nutrients and waste products
100
function of white blood cells
• involved in phagocytosis
• some white blood cells produce antibodies
101
what is a pathogen
a disease causing organism
102
2 ways body can respond to detecting a pathogen
• lymphocytes produce antibodies that are specific to antigens on pathogens
• phagocytes can engulf the pathogen
103
describe the double circulatory system in mammals
• heart pumps blood to lungs
• oxygenated blood returns to the heart and pumped around body
104
difference in function between arteries, veins and capillaries
• arteries - carry blood away from heart
• veins - carry blood towards heart
• capillaries- flow close to tissues for exchange
105
describe structure of arteries
have thick walls made of muscle and elastic tissue and a small lumen to transport blood under high pressure
106
describe structure of veins
• have less muscle and elastic tissue than arteries
• have a larger lumen as blood is at lower pressure
• have valves to prevent backflow
107
describe structure of capillaries
have thin walls about 1 cell thick to allow easy exchange of substances at the tissues
108
describe blood flow through the right side of heart
• deoxygenated blood flows into right atrium from vena cava
• this blood passes through right AV valve into right ventricle
• blood then pumped out of heart to the lungs though right SL valve and unto pulmonary artery
109
describe blood flow through left side of the heart
• blood enters into left atrium from pulmonary vein
• the blood is then pumped through left AV valve into left ventricle
• blood then pumped out through left SL valve and into aorta
110
name of the wall that separates right and left sides of heart
the septum
111
name of the artery taht supplies the heart tissue with blood
the coronary artery
112
what type of muscle is the heart made of
cardiac muscle
113
why is the wall of left ventricle thicker than wall of right ventricle
• left ventricle has to pump blood further distance around whole body
• blood needs to be under a higher pressure
114
what does adrenaline do to heart rate
• increases heart rate
• as it triggers 'flight or fight' reflex
115
3 parts of the body that adrenaline affects
• increases heart rate
• dialates pupils
• increases breathing rate
116
why does heart rate increase during exercise
• more muscle movement needs more energy from respiration
• muscle tissues need to have a supply of oxygen to carry out respiration
• so the heart needs to pump faster to provide oxygen
117
what is coronary heart disease
when artery providing heart tissue with blood becomes blocked
118
3 common risk factors for CHD
• smoking
• poor diet
• lack of exercise
119
what 2 waste gases do plants produce and what processes produce them
Oxygen - waste product of photosynthesis
Carbon dioxide - waste product of respiration
120
function of kidneys
• regulate volume and concentration of urine
• remove water and regulate body water content
121
give 3 waste products produced in the body
• urea
• carbon dioxide
• excess salt and water
122
name 3 excretory organs
• lungs
• kidneys
• skin
123
Define homeostasis
maintaining a constant interal environment despite external change
124
3 conditions that need to be controlled within the body
• temperature
• water levels
• blood glucose concentration
125
3 main parts to a coordinated response
• a stimulus
• a receptor
• an effector
126
What does auxin trigger
• auxin triggers growth of the main stem of the plant
• (and it inhibits growth of side shoots)
127
What is phototropism + which part of a plant is positively phototropic
• phototropism - growth of a plant towards a light source
• the shoots are positively phototropic
128
What is geotropism + which part of a plant is positively geotropic
• geotropism - growth of a plant towards pull of gravity
• roots are positively geotropic
129
How does auxin cause the shoots to grow towards light source
• auxin collects on shaded side
• auxin promotes cell growth
• the shoot curves towards light
130
3 differences between nervous and hormonal communication
• N - uses nerve cells and impulses
H - secreted by glands and travel in blood
• Nervous is generally much faster
• Hormonal brings longer lasting responses
131
What is the difference between central nervous system + peripheral nervous system
CNS - brain and spinal cord
PNS - every other part of the nervous system
132
How is an impulse transmitted between 2 neurones
• The impulse reaches the end of 1 neurone
• neurotransmitter released and diffuse across the gap
• a new impulse is triggered in the next neurone
133
What is a stimulus
a change in the environment
134
What type of neurone connects a receptor to the CNS
a sensory neurone
135
What is an effector
• a part of the body that brings the response to a stimulus
• like a muscle or a gland
136
what type of neurone connects the CNS to an effector
a motor neurone
137
describe the reflex arc
• stimulus detected by receptor
• impulse passed along sensory neurone to CNS
• impulse passed along motor neurone to effector
• effector brings about the response
138
describe sequence of events involved in removing a hand away from a hot flame
• thermoreceptors in hand detect heat of flame
• an impulse sent along sensory neurone
• the impulse passes through relay neutones in the CNS
• the impulse then passes along a motor neurone and triggers muscles in the arm to move the hand away
139
what is cornea and it's function
• transparent layer infeont of eye
• protects the eye from damage
140
what is the iris and it's function
• The coloured ring around the pupil
• controls it's diameter
141
What is the pupil and it's function
• The hole in the middle of the iris
• let's light into the eye
142
What is the optic nerve and it's function
• The nerve coming out the back of the eye
• sends signals to the brain
143
function of the lens
focuses the light rays onto the retina
144
What is the retina and it's function
• The back part of the eye
• converts visual stimulus into electrical impulses
145
What do the ciliary body and suspensory ligaments do
they control the shape of the lens
146
How does the eye focus of near objects
• ciliary muscles contract and suspensory ligaments relax, causing lens to thicken
• thicker lens causes light to refract more
147
how does the eye focus on far away objects
• ciliary muscles relax and suspensory ligaments stretch, which makes lens thinner
• thinner lens causes light to refract less
148
how does the eye respond to bright light
it's contracts, making pupil smaller and letting in less light
149
how does the eye respond to a lack of light
iris relaxes which makes pupil larger and let's in more light
150
coordination and response : why foes temperature need to be controlled
• to provide a suitable environment for enzymes
• so they can work fastes at optimum temperature
151
2 processes involving skin that cool the body down
sweating - cools body by evaporation
vasodilation - allows blood to flow closer to the surface of the skin where it can be cool
152
describe process of vasodilation
• body detects a rise in temperature
• blood vessels supplying the capillaries at the skin surface dilate (muscles I'm the vessels relax)
• more blood flows closer to the skin where it can cool
153
3 processes that work to keep body warm
• vasoconstriction
• shivering
• erection of hairs on skin
154
describe process of vasoconstriction
• body detects a top in temperature
• blood vessels supplying the capillaries at the skin surface constrict (muscles in the vessels constrict)
• less blood flows closet to the skin surface so less heat is lost to surroundings
155
what are hormones
• chemical messengers
• secreted by glands of the endocrine system into the bloodstream
156
what does insulin do in the body
decreases blood glucose concentration
157
where is insulin secreted from
the B cells of the pancreas
158
what does testosterone do
• main male sex hormone
• involved in growth of testes and penis
• triggers many changes in males during puberty
159
where is testosterone secreted from
the testes
160
when in adrenaline secreted
during times of anxiety, fear or stress
161
where is adrenaline released from
the adrenal glands
162
give 3 affects of adrenaline in the body
• increases heart and breathing rate
• increases blood glucose concentration
• dialates pupils
163
what does oestrogen do
causes the uterus lining to thicken
164
where is oestrogen secreted from
the ovaries
165
what hormone does oestrogen inhibit
follicle stimulating hormone (FSH)
166
what does progesterone do
maintains the womb lining
167
where is progesterone secreted from
the ovaries
168
what hormone does progesterone inhibit
follicle stimulating hormone (FSH)
